bootstrap-initrd

commit: e71d9b8795f325678cec28b0c29afe0aa7a63adc
parent d8e0f335ee317f6793305c1d175319f4976708b3
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Tue, 30 Apr 2024 01:40:04 +0200

cp-stub.c: new

Diffstat:
A
cp-stub.c
130
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
M
init.sh
4
+---
M
make-root.sh
2
+-

3 files changed, 132 insertions(+), 4 deletions(-)
diff --git a/cp-stub.c b/cp-stub.c
@@ -0,0 +1,130 @@
+// utils-std: Collection of commonly available Unix tools
+// SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
+// SPDX-License-Identifier: MPL-2.0
+
+#define _POSIX_C_SOURCE 200809L
+#define _GNU_SOURCE // copy_file_range
+
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>  // linkat, AT_SYMLINK_FOLLOW
+#include <limits.h> // PATH_MAX
+#include <stdbool.h>
+#include <stdio.h>  // fprintf
+#include <string.h> // strerror
+#include <sys/stat.h>
+#include <unistd.h> // getopt, copy_file_range
+
+static int
+do_copy(char *src, char *dest)
+{
+	assert(errno == 0);
+	int src_fd = open(src, O_RDONLY);
+	if(src_fd < 0)
+	{
+		fprintf(stderr, "cp: Failed opening file '%s' for reading: %s\n", src, strerror(errno));
+		return -1;
+	}
+
+	struct stat src_stat;
+	if(fstat(src_fd, &src_stat) < 0)
+	{
+		fprintf(stderr, "cp: Failed getting status for target '%s': %s\n", dest, strerror(errno));
+		return -1;
+	}
+
+	int dest_fd = open(dest, O_CREAT | O_WRONLY | O_TRUNC, src_stat.st_mode & 0777);
+	if(dest_fd < 0)
+	{
+		fprintf(stderr, "cp: Failed create-opening file '%s' for writing: %s\n", dest, strerror(errno));
+		return -1;
+	}
+
+	off_t len = src_stat.st_size;
+	off_t ret = -1;
+	do
+	{
+		ret = copy_file_range(src_fd, NULL, dest_fd, NULL, len, 0);
+		if(ret == -1)
+		{
+			fprintf(stderr,
+			        "cp: Error: Failed copying data from '%s' to '%s': %s\n",
+			        src,
+			        dest,
+			        strerror(errno));
+			return -1;
+		}
+		len -= ret;
+	} while(len > 0 && ret > 0);
+
+	if(close(src_fd) < 0)
+	{
+		fprintf(stderr, "cp: Error closing '%s'\n", src);
+		return -1;
+	}
+
+	if(close(dest_fd) < 0)
+	{
+		fprintf(stderr, "cp: Error closing '%s'\n", dest);
+		return -1;
+	}
+
+	assert(errno == 0);
+
+	return 0;
+}
+
+static void
+usage()
+{
+	fprintf(stderr, "Usage: cp source... destination\n");
+}
+
+int
+main(int argc, char *argv[])
+{
+	int c = -1;
+	while((c = getopt(argc, argv, ":")) != -1)
+	{
+		switch(c)
+		{
+		case '?':
+			fprintf(stderr, "cp: Unknown option '-%c'\n", optopt);
+			usage();
+			break;
+		}
+	}
+
+	assert(errno == 0);
+
+	argc -= optind;
+	argv += optind;
+
+	if(argc == 2)
+	{
+		if(do_copy(argv[0], argv[1]) < 0) return 1;
+	}
+	else
+	{
+		char *dest            = argv[argc - 1];
+		char target[PATH_MAX] = "";
+
+		for(int i = 0; i < argc - 1; i++)
+		{
+			char *src = argv[i];
+
+			char *src_sep      = strrchr(src, '/');
+			char *src_basename = src_sep != NULL ? src_sep + 1 : src;
+
+			if(snprintf(target, PATH_MAX, "%s/%s", dest, src_basename) < 0)
+			{
+				fprintf(stderr, "cp: Failed joining destination '%s' and target '%s'\n", dest, src);
+				return 1;
+			}
+
+			if(do_copy(src, target) < 0) return 1;
+		}
+	}
+
+	return 0;
+}
diff --git a/init.sh b/init.sh
@@ -26,15 +26,13 @@ build_awk() {
 }
 
 build_stubs() {
-	for i in ls mv grep
+	for i in ls mv grep cp
 	do
 		$CC $CFLAGS -o "/bin/$i" "/${i}-stub.c" || die "Failed compiling $i stub"
 	done
 	ln -s grep /bin/egrep || die
 	ln -s grep /bin/fgrep || die
 	ln -s /utils-std-*/cmd/cat /bin/sort || die
-	# Yeah, I know, copying != linking
-	ln -s /utils-std-*/cmd/ln /bin/cp || die
 }
 
 build_bmake() {
diff --git a/make-root.sh b/make-root.sh
@@ -69,7 +69,7 @@ cp "${WORKDIR}/init.c" ./init || die "copying init"
 sed -i '1i#!/bin/tcc -run' ./init || die "failed adding tcc shebang to init"
 chmod 755 init || die "init chmod"
 
-for i in init.sh ls-stub.c mv-stub.c grep-stub.c
+for i in init.sh ls-stub.c mv-stub.c grep-stub.c cp-stub.c
 do
 	cp -p "${WORKDIR}/$i" ./ || die "failed copying $i"
 done